The invention relates to an EE (electric-eye) exposure apparatus for use in a bladed shutter camera.
Conventional EE cameras are constructed such that an EE mechanism is given a selected parameter for establishing an amount of exposure so as to permit a selected photographic operation according to the programmed EE (i.e. fully automatic operation), an EE followed shutter speed (i.e. an EE operation in which the shutter speed is initially preset), an EE followed diaphragm opening (i.e. an EE operation in which the diaphragm aperture is initially preset) scheme and the like. As a result, a photographer has to choose a suitable camera depending on the intended photographic operation. Considering a programmed shutter, for example, combinations of diaphragm apertures and effective exposure periods are predetermined for selected values of exposure. This removes the need for any scale adjustment prior to a photographic operation, and a proper amount of exposure is assured merely by depressing a shutter button. However, inconvenience is caused in that a photographer can not choose a desired combination of a particular diaphragm aperture and an effective exposure period. Consequently, a programmed shutter is inadequate for use with certain photographic techniques such as choosing a shutter speed below a limit above which oscillations may be caused or choosing a depth of focus in accordance with a desired diaphragm aperture by viewing the deflection of a meter pointer within a view finder.
While it may be desired that a single camera be usable in two photographic operations such as those of a programmed type and an electric-eye followed shutter speed type, this involves certain difficulties as will be discussed below. Specifically, the time interval during which shutter blades are maintained open is controlled by a delay mechanism which engages an anchor with an escape wheel. In a programmed type operation, the opening must vary with time according to a triangular form as is well known, and this requires the delay mechanism to be engaged with a shutter mechanism including a shutter operating ring or the like, before a shutter release is operated. As a consequence, when switching from a programmed type operation to a shutter speed preset operation, the shutter operating ring or the like must be adjusted with the governor in engagement, which results in a slow switching operation. If an immediate release operation is attempted, the release operation may take place before the switching operation is completed. On the other hand, if the arrangement is adapted for a preset shutter speed operation, the shutter will rapidly move in the opening direction and the delay mechanism will engage the shutter mechanism only when the latter is fully open, therefore precluding a triangular opening profile, which is desired in a programmed operation, from being achieved.